Submitted to: Plant Protein Club 1998 Annual Symposium
Publication Type: Abstract Only
Publication Acceptance Date: July 16, 1998
Publication Date: N/A
Technical Abstract: Tortula ruralis is a moss capable of surviving drying of its vegetative tissue, i.e., it is considered a desiccation-tolerant plant. The currently accepted hypothesis is that the desiccation-tolerance mechanism employed by T. ruralis is based upon rapid repair of cellular damage incurred during rehydration. It is our working hypothesis that much of the repair of desiccation induced damage results from the activity of rehydrins, a group of proteins whose synthesis is enhanced upon rehydration. Previous work has demonstrated that the synthesis of these proteins is controlled mainly at the translational level. However during drying, T. ruralis accumulates rehydrin mRNAs that are stored in the dried gametophytes ready for use upon rehydration. Our work indicates that this accumulation is a result of increased mRNA stability (formation of mRNPs) along with a presumed increase in transcription. We have isolated and sequenced a number of rehydrin cDNA clones, one of which, Tr288, will be addressed in this poster. During dehydration, Tr288 mRNA is detected in sucrose and cesium gradients at positions consistent with the formation of mRNA particles (mRNPs). Upon rehydration the transcripts appear to be released from storage for translation. The Tr288 protein sequence deduced from translation of the cDNA exhibits features that are similar to proteins known to be involved in desiccation and water stress responses (e.g., high glycine content and a single dehydrin motif) but does not exactly fit any of these groups. In this poster we will discuss Tr288 gene structure, expression patterns and explore possible functions for this unique rehydrin and its role in desiccation-tolerance.